Raw diffraction data and reproducibility

Abstract

In recent years, there has been a major expansion in digital storage capability for hosting raw diffraction datasets. Naturally, the question has now arisen as to the benefits and costs for the preservation of such raw, i.e., experimental diffraction datasets. We describe the consultations made of the global structural chemistry, i.e., chemical crystallography community from the points of view of the International Union of Crystallography (IUCr) Committee on Data, of which JRH was the Chair until very recently, and the IUCrData Raw Data Letters initiative, for which LKB is the Main Editor. The monitoring by the CCDC of CSD depositions which cite the digital object identifiers of raw diffraction datasets provides interesting statistics by probe (x-ray, neutron, or electron) and by home lab vs central facility. Clearly, a better understanding of the reproducibility of current analysis procedures is at hand. Policies for publication requiring raw data have been updated in IUCr Journals for macromolecular crystallography, namely, that raw data should be made available for a new crystal structure or a new method as well as the wwPDB deposition. For chemical crystallography, such a step requiring raw data archiving has not yet been recommended by the IUCr Commission on Structural Chemistry.

FIG. 1.

Trust in science is built up from different facets. Reproduced with permission from Helliwell and Massera, J. Appl. Cryst. 55, 1351–1358 (2022). Copyright 2022 IUCr Journals.

FIG. 2.

The benefits of having access to raw data, as identified by the survey respondents. Reproduced with permission from Coles and Sarjeant, see https://www.iucr.org/news/newsletter/volume-28/number-1/raw-data-availability-the-small-molecule-crystallography-perspective for “IUCr Newsletter (2020).” Copyright 2020 IUCr Journals.

FIG. 3.

The procedure used by the CCDC (left) and an example of raw diffraction data archiving (right) of which data can be found at https://dx.doi.org/10.5517/ccdc.csd.cc20sx7z.

FIG. 4.

The portion of structures with raw data DOIs and diffraction probes used.

FIG. 5.

In total, 162 structures have raw data, distributed over the various data repositories as shown on the left. The number of papers having raw data DOIs is shown on the right.